Welcome to AA.
Letting the tapwater "sit" will dissipate the Chlorine in it, but if your supply has Chloramine you're still going to be in big trouble when you add it to the tank. What chemicals exactly did you buy from the
LFS? The people on the board will be able to tell you which ones are necessary (like a water conditioner) and which ones can go straight back to the store (pH Down anyone?).
Most importantly, don't buy any fish yet. The first thing you want to do is plan out your tank and do research, which I'm sure is what led you here. It's also notable that the
LFS does not always have your best interests in mind, and that the employees there may actually know diddly squat about keeping fish. Take everything you hear from them (and from other sources
) with a liberal application of salt.
In the meantime, start hunting down some articles on the web that will help you, and perhaps a few of the fish encyclopedias floating around at libraries and stores. And feel free to ask all kinds of questions..
And be prepared to answer some. How big is your tank?
Here are some good places to go to research things further:
http://faq.thekrib.com/begin.html - Beginner
FAQ
http://freshaquarium.about.com/cs/beginnerinfo/ - Another Beginner
FAQ
http://www.liveaquaria.com/product/categ.cfm?siteid=21&pCatId=830 - Fish Profiles
http://www.fishbase.org/search.cfm - Definitive Fish Profiles
http://www.aquariacentral.com/species/fresh.shtml - Still More Fish Profiles!
You're sure to get some recommendations too once you list your tank specs. In fact, if you could list the following it would be really helpful--
Tank Size (Dimensions and Gallons both if possible-- if you only have Gallons that's okay though)
Temperature (and Heater Brand)
Filtration (Type, Brand, and Model)
Substrate (Gravel, Sand, etc.)
Decor (Cheese, Fake Plants, Live Plants, Caves, etc.)
Even if you don't have everything yet, if you could mention what kinds of fish you might like it will help the board direct you to species that would be appropriate for your tank.
Hope that helps.